Toxicity of Un‐ionized Ammonia and High pH to Post‐larval and Juvenile Freshwater Shrimp Macrobrachium rosenbergii

Abstract

Post‐larval and juvenile Macrobrachium rosenbergii were exposed for 72 h at 29 C to four pH levels (8.5, 9.0, 9.5, 10.0) and four concentrations of un‐ionized ammonia‐nitrogen (0, 1, 2, and 3 mg/L NHj‐N). Results indicated potentiation between NH3 and high pH. Juveniles were more tolerant of high pH and NH3 than post‐larvae. For post‐larvae, estimates of 72 h LC50 for pH were 9.43, 9.21, and 8.71 at 0, 1, and 2 mg/L NH3‐N, respectively; 72 h LC50 estimates for NH3‐N were 2.18 and 1.45 mg/L at pH levels of 8.5 and 9.0, respectively. For juveniles, estimates of 72 h LC50 for pH were 9.91, 9.56, 9.04, and 8.76 at 0, 1, 2, and 3 mg/L NH3‐N, respectively; 72 h LC50 estimates for NH3‐N were 2.02 and 0.54 mg/L at pH 9.0 and 9.5, respectively. In pond culture of M. rosenbergii, high pH levels can cause mortality at stocking. The 72 h data can be used as an indication of safe stocking levels of pH and ammonia. These data suggest that post‐larvae should not be exposed to pH > 9.0 nor to NH3‐N > 1 mg/L in the pH range 8.5–9.0 and juveniles should not be exposed to pH > 9.5 nor to NH3‐N > 0 mg/L at pH 9.5, > 1 mg/L at pH 9.0, or > 2 mg/L at pH 8.5.

Meat and Bone Meal as Partial Substitute for Fish Meal in Nursery Diet for Giant Freshwater Prawn, Macrobrachium rosenbergii (de Man)

“…The DO content of 6.5–8.4 mg/L found in the present study, higher than those of the above studies, might be because of the continuous use of an aerator. The range of total ammonia content found in the experimental system (0.01–0.25 mg/L) was lower than the safe level of 1 mg/L reported for M. rosenbergii PL (Strauss et al 1991). This very low value of ammonia observed might be because of effective functioning of the biofilters in the system.…”

Polyculture of Nile Tilapia, Oreochromis niloticus, Either Confined in Cages or Unconfined in Freshwater Prawn, Macrobrachium rosenbergii, Ponds

“…Overall means (±SE) for TAN (mg/L), un‐ionized ammonia‐nitrogen (mg/L), nitrite‐nitrogen (mg/L), pH, total alkalinity (mg/L), total hardness (mg/L), and calcium hardness (mg/L) were: 0.93 ± 1.78, 0.20 ± 0.13, 0.04 ± 0.06, 8.4 ± 2.2, 71.9 ± 33.7, 131.0 ± 11.1, and 103.6 ± 10.0, respectively. All water quality measurements were considered suitable for good growth and survival of both prawn and tilapia (Straus et al 1991).…”

Effect of ammonia-N on growth and feeding of juvenile Macrobrachium rosenbergii (De-Man)

“…Similar explanations were put forward by Mallasen and Valenti (2005) for larval development and survival of the giant river prawn M. rosenbergii at different NH 3 concentrations. Straus et al . (1991) suggested a similar explanation for the growth and survival of post‐larval and early juveniles of the prawn M. rosenbergii at different NH 3 levels.…”

“…Mallasen and Valenti (2005) reported significantly lower survival rates (0–20%) of M. rosenbergii larvae at total ammonia concentrations from 1 to 8 mg L −1 (0.43–3.41 mg L −1 of non‐ionized ammonia) in pH 9, although the weight gain (1.572–2.931 mg range) of larvae did not differ among the different ammonia concentrations. Straus, Robinette and Heinen (1991) studied the toxic effect of non‐ionized ammonia (NH 3 ) on post‐larval and early juvenile of M. rosenbergii and reported that early juveniles (around 0.5 g size) were more tolerant of high NH 3 than postlarvae. However, information regarding the effects of total ammonia on late juveniles (around 4.0 g size) phase of this species is not available.…”